A gas valve with ceramic disc element

ABSTRACT

The invention relates to a gas valve unit, comprising a body having an inlet channel and an outlet channel in gas flow connection via an inner chamber surrounded by body a stationary disc element fixed in the inner chamber and having a through hole thereon that opens into the gas outlet channel ; a rotating disc element with an inner wall rotatably overlapping a front wall of the stationary disc element and a cavity that access to the outlet channelthrough the through holewhen rotated. The front wall and the inner wall of the stationary disc elementand the rotating disc element facing each other, respectively, are at least partially made of ceramic material.

TECHNICAL FIELD

The invention relates to adjustable gas regulating valves forcontrolling the gas flow rate via control elements having the structureof the rotatable disc.

BACKGROUND OF THE INVENTION

The gas regulating valve units are ready-to-install units in householdor outdoor appliances are provided between a burner and a gas supply.Gas valve units generally operate by rotating a control rod attached tothe body by means of a rotary knob. Angular position of the knobdetermines the gas flow rate that the gas regulating valve limits.

WO2018216044A gas valve unit comprising a body provided with an inlet,fluidically connectable to a gas source and to at least one outlet, amain chamber, defined at least in part in said body, put into fluidcommunication with said gas inlet and provided with main outlet hole putinto fluid communication with said outlet, a disc-shaped element whichis housed in said main chamber, is provided with at least one throughopening defining at least two zones, having a mutually different passagesection in order to put said main chamber into communication with saidmain outlet hole.

SUMMARY OF THE INVENTION

The object of the invention is to increase the lifetime of disc type gasvalves.

In order to achieve abovementioned objects, the invention comprises agas valve unit, including a body having an inlet channel and an outletchannel in connection with an inner chamber that it surrounds so as toprovide gas flow; a stationary disc element fixed in the inner chamberand having a through hole thereon that opens into the gas outletchannel; a rotating disc element with an inner wall rotatablyoverlapping a front wall of the stationary disc element and a transferopening that rotates to reach the outlet channel through the throughhole when rotated. Also, in the gas valve unit, the front wall and theinner wall of the stationary disc element and the rotating disc elementfacing each other, respectively, are at least partially made of ceramicmaterial. Thereby, during the rotation of the rotating disc element onthe stationary disc, the friction forces are reduced and the lifetime ofthe product is increased. The expression “partly made of ceramicmaterial” should be interpreted as the use of a ceramic materialcoating, insert or completely ceramic material in the contacting partsof the front wall and inner wall.

In a preferred embodiment of the invention, the stationary disc elementand the rotating disc element are made of solid ceramic material. Inthis case, it is possible to manufacture and use the stationary discelement or the rotating stationary disc in one piece by powdermetallurgy or similar method. Further, the torque required to rotate thegas valve unit does not change even in case of wear caused by themovement of the fixed and rotating disc elements on each other in solidmaterial. This allows the user to adjust the gas regulation withoutdifficulty even after long periods of use.

A preferred embodiment of the invention comprises a rear wall parallelto the front wall and the stationary disc element is coupled from aperipheral wall between the front wall and the rear wall to an innerwall forming the inner periphery of the inner chamber. Thus, the impactforces in the direction of rotation applied to the stationary discelement via the rotating disc element form a reaction force byperipherally abutting on the inner periphery of the inner chamber.

A preferred embodiment of the invention includes a flexible gasket thatis compressed towards the gas outlet channel in a gas-tight waysurrounding the passage hole on the planar rear wall. The flexiblegasket can be compressed such that it will provide sealing against apredetermined gas pressure by a pre-stress, together with the stationarydisc element being mounted.

A preferred embodiment of the invention includes an oil film which isprovided between the front wall and the inner wall, surrounding thethrough hole and the transfer opening in a gastight way and adjusted toa predetermined viscosity so as to allow rotation on one another. Theoil film extends between the stationary disc element and the movabledisc element, filling the gaps that may occur due to tolerancedifferences during production and ensuring gas tightness. It alsoreduces friction, allowing the rotating disc element to be rotated withless torque than directly contacting the stationary disc element.

A preferred embodiment of the invention includes a plurality of pocketsprovided on the inner wall that store the oil droplet by feeding the oilfilm during the rotation of the rotating disc element. The pocketsensure that the film remains at a critical sealing thickness such thatit prevents the oil film from losing its function over time with therotational movement.

A preferred embodiment of the invention includes a control rod extendingvertically outward by being attached to an outer wall of the rotatingdisc element. The control rod allows the rotating disc element to berotated directly with the torque applied by the operator. Preferably,the control rod and the rotating disc element are concentric. Thus, itis possible, for example, to rotate the control rod with a control knob.

A preferred embodiment of the invention includes a cover that surroundsthe control rod from one end and is fixed to the body from the otherend. The cover prevents the materials such as dust and dirt that willaffect the rotation from the outside environment from entering betweenthe rotating disc element and the stationary disc element withoutimpeding the rotational movement.

A preferred embodiment of the invention includes a compression springadjusted inside the cover such that it abuts against the inside of thecover from one end and presses the rotating disc element from the otherend. The compression spring ensures that the flexible gasket iscompressed by the stationary disc element against the correspondinginner wall in the inner chamber, enabling a sealed flow in the bodydespite the gas pressure.

In a preferred embodiment of the invention, the stationary disc elementand the rotating disc element are manufactured or coated from a materialselected from the group consisting of alumina, silicon carbide, siliconnitride and zirconia. It has been determined that the selected group ofmaterials provides a safe application against the passage of flammablegas therethrough. Also, surprisingly, it has been observed that saidgroup wears less in the case of rotational movement compared to otherceramic materials.

In order to achieve the abovementioned objects, the invention is a gascooker or heating device to which a gas valve unit is adapted accordingto any of the embodiments described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear perspective view of a representative embodiment of thegas regulating valve unit of the invention, with the inner chambervisible.

FIG. 2 is a perspective view from the rear wall of the stationary discelement in a representative embodiment of the ceramic gas regulatingvalve unit.

FIG. 3 is a perspective view from the inner wall of a rotating discelement suitable for use with the stationary disc element shown in FIG.2 .

FIG. 4 is a side view of a representative embodiment of the gasregulating valve unit of the invention.

FIG. 5 is the H-H cross-sectional illustration of the gas regulatingvalve given in FIG. 4 .

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the development of the invention has beendescribed without any limitation and only with reference to the examplesfor a better explanation of the subject.

In FIG. 1 , there is shown a representative embodiment of the gas valveunit of the invention with a safety outlet (17) in a partialcross-section so that an inner chamber (1) can be visible. The gas valveunit has a structure in which a flammable gas (e.g. natural gas) istransferred from an inner chamber (1) sealed by a metal body (10) toform a gas flow with an adjustable flow rate. The body (10) hassegmented structure and the parts are sealed tightly to each other withgasket connections. An upper part (22) of the two-piece control rod (20)attached to the body (10) from the front, extends from its free end tothe inner chamber (1) so that it rotates around its own axis by beingconnected to a control knob (not shown). A lower part (24) of thecontrol rod (20) in the form of a pusher arm, which is movably connectedwith the upper part (22) of the control rod, extends to a safetyassembly (60) located at the end of the inner chamber (1).

A stationary disc element (30) is fixed against axial and rotationalmovements in the inner chamber (1) by passing the inner chamber (1)perpendicular to the control rod (20) in transverse sections. Thestationary disc element (30) is made of ceramic material and has ahorizontal, flat form. From a segmented curved circumferential wall (33)of the inner chamber (30), it fits into a retainer boundary (18) havingcorresponding concave recesses surrounding the inner chamber (1) anddefining the inner boundary of the inner chamber (1) from behind. Afront wall (35) parallel to and opposite to a rear wall (31) of thestationary disc element (30) and a rotating disc element (40) from oneinner wall (41) are overlapped in the inner chamber (1). An outer wall(43) of the rotating disc element (40) extends outward in a truncatedconical structure such that it valveers. A rubber flexible sealinggasket (50) is placed on the rear Wall (31) of the stationary discelement (30). The gasket (50) completely surrounds the auxiliary hole(36), which is longitudinally drilled, by means of a through hole (34)of the stationary disc element (30), respectively, and a through hole(32) at an angular distance aligned around thereof. Thereby, thestationary disc element (30) abuts the gasket (50) against the flat rearwall (31) of the body (10) forming the forehead part of the innerchamber (1). Thus, the through hole (32) reaches a gas outlet (14) in asealed way by means of the gasket (50).

The body (10) has an inlet (12) for gas supply and a gas outlet (14)associated therewith to selectively transmit fluid. The inlet (12) andthe gas outlet (14) are circular and form a passage path for gas flowfrom the inner chamber (1) with the connection of the cylindrical inletchannel (15) and the outlet channel (16), respectively. In addition, asafety outlet (17) parallel to the gas outlet (14) is connected to theinner chamber (1) on the body (10) so as to provide gas transmission.

In FIG. 2 , the one-piece ceramic stationary disc element (30) is shownin perspective from its rear wall (31). The stationary disc element (30)in the form of a flat plate with a circumferential wall (33) formed bydividing the surroundings thereof with adjacent handle parts (331), hasa channel (37) opened on its flat rear wall (31). The rubber gasket (50)corresponding to the channel (37) fits tightly. The depth of the channel(37) is adjusted below the height of the flexible gasket (50) in freestate so that it will allow the flexible gasket (50) to partiallyprotrude from the rear wall (31). A circular central hole (34) is cut inthe center of the stationary disc element (30). Adjacent to this, thereis a block (38) surrounded by the channel (37). The block (38) is in theform of a circular projection. The through hole (32) adjacent to thecentral hole (34) in the opposite direction to the block (38) is in anelongated form in the radial direction. An auxiliary through hole (36)is provided on the stationary disc element (30) as being adjacent to thethrough hole (32) adjacent to the central hole (34). The auxiliarythrough hole (36) is circular and has a small area than the through hole(32). The central hole (34), the through hole (32) and the auxiliarythrough hole (36) are extended from the channel (37) to the rear wall(31) with a flue part extending along the depth of the channel (37).

In FIG. 3 , the one-piece ceramic rotating disc element (40) is shown inperspective from the inner wall 41 of the inner chamber (1), which fitson the corresponding forehead. The rotating disc element (40) is in theform of a truncated cone and its wide circular part forms the planarinner wall (41) thereof. In the center of the inner wall (41) there is amounting hole (44) that is drilled from one end to the other. Themounting hole (44) has an expansion chamber (45) which is gradually andradially enlarged towards the inner wall (41). A side portion of theexpansion chamber (45) includes a spirally extending cavity (42) in theinner wall (41) at radial distance to the mounting hole (44). The cavity(42) runs radially in the inner wall (41) with increasing width anddepth, starting from a rounded rear end (421) forming a narrow portion(422) and extends continuously from a front end (424) through a widepart (423) that joins the expansion chamber (45) to the mounting hole(44) so as to provide gas transmission. At the junction of the expansionchamber (45) and the front end (424), the expansion chamber (45) leadsthrough a passageway to a baffle wall (425), which is the outer part ofthe front end (424). The cavity (42) is provided adjacent and at adistance with a circular circumferential edge (46) of the inner wall(41). An L-like auxiliary channel extends from one end of the front end(424) to the expansion chamber (45) at a wide angle. Multiple pockets(47) are opened in the inner Wall (41) that form a lubricating channelin a multiple hemispherical structure distributed in planar sections.The pockets (47) are distributed on the inner wall 41 along the radialline delimited by the cavity (42). The pockets (47) are obtained byforming the planar inner wall (41) such that the ceramic material formsa cavity in its structure.

The rotating disc element (40) is placed concentrically on thestationary disc element (30). Both are made of alumina. The inner wall(41) of the rotating disc element (40) overlaps the front wall (35) ofthe stationary disc element (30). In the closed position, the cavity(42) is blocked by a flat portion of the front wall (35). On the otherhand, the mounting hole (44) is coaxial with the central hole (34) andis opened to allow gas passage to each other. The spiral-shaped cavity(42) is spaced radially at an accessible 90° angle, with its front end(424) facing the through hole (32). The cavity (42) extends radiallyoutward from the expansion chamber (45) to reach the baffle wall (425)and wherein it decreases in both cross section and depth from the wideportion (423) to the opposite rear end (421) where the narrow portion422 is located. Since the control rod (20) extends axially through acylindrical passage channel formed by the mounting hole (44) and thecentral hole (34), the gas flow supplied from the inlet (12) from thedistance between the control rod (20) and the transition channel isfirst taken to the expansion chamber (45), then it hits the baffle wall(425) and proceeds from the front end (424) to the wide part (423), andfrom there through the cavity (42), which narrows both in width anddepth, to the rear end (421). In the closed position, the cavity (42)completely covers the planar portion of the front wall (35) of thestationary disc element (30) in a sealed manner. In the maximum gasposition in which the gas is directed to the gas outlet (14) at maximumflow rate, the wide part (423) is aligned with the passage hole (32)completely. In this case, a front edge (426) of the cavity (42) alignswith the through hole (32) and the entire area of the through hole (32)lies within the cavity (42). Thus, the stationary disc element (30)transmits the gas flow to the gas outlet (14) through the through hole(32).

In FIG. 4 , the gas regulating valve unit is shown from the left. Here,the upper part (22) of the control rod (20) extending outward is visibleon the body (10). The upper part (22) is mounted to the body (10) undera cover (26) rotating around its axis. The cover (26) is a hollowconical piece. At least two tabs (not shown) extend on the wide mouth ofthe cover (26) facing the body (10), wherein pressure is exerted on thestationary disc element (30) by the forms opened on the body (10)through the face corresponding to the body (10) from the mentioned tabs.Thus, sealing is provided by mechanical compression to the gasket (50)positioned on the stationary disc element (30).

In FIG. 5 , H-H section is shown on a vertical axis passing through theinlet part (12). The retainer boundary (18) in which the stationary discelement (30) is placed from the circumferential wall (33) in the innerchamber (1) has recesses suitable for the handle parts (331). Thestationary disc element (30) is placed on the retainer boundary (18) andfixed in the body (10) so as to divide the inner chamber (1). The gasflow (shown by arrows) supplied from the inlet part (12) proceedsthrough an inlet channel (15) in the body (10) and reaches the innerchamber (1).

By pushing the control rod (20) from the upper part (22) to which thebutton is attached, the gas flow is started by pushing the tab of thesafety assembly (60) through the lower part (24). A compression spring(28) wound on the front end of the lower part (24) pushes the upper part(22) towards its original position. Meanwhile, the gas from the inletchannel (15) accumulated in the inner chamber (1) first reaches the rearwall (31), then stopped over the stationary disc element (30) and passesthrough the central hole (34) and reaches the mounting hole (44) of therotating disc element (40). The gas flow proceeding to the cavity (42)therefrom through the expansion chamber (45), reaches the stationarydisc element (30) again, this time from its front wall (35) adjacent tothe cavity (42) and is directed through the wide part (423) of thecavity (42) to the through hole (32) located above thereof. The gasflow, which is delivered therefrom to an orifice reaching an outletchannel (16) from which the gas is discharged, reaches the gas outlet(14).

For regulating the gas flow, the control rod (20) is rotated in itsreach axis. The control rod (20) is connected from its upper part (22)to an adapter socket (48) located at the front end (424) of the rotatingdisc element (40). Thereby, when the control rod (20) is rotated, therotating disc element (40) rotates. The wide part (423) of the cavity(42) that reaches the through hole (32) by turning the rotating discelement (40) 90° from the closed position, is blocked by the planar partof the front wall (35) while rotating is continuing, and the throughhole (32) is aligned with the narrowing section of the cavity (42). Inthe last step, the narrow part (422) is aligned with the auxiliarythrough hole (36). The auxiliary through hole (36) has a narrower areathan the through hole (32) and is aligned with the narrow portion (422)of the spiral cavity (42) to ensure the minimum gas flow rate.

In the inner chamber (1), first the stationary disc element (30) andthen the rotating disc element (40) are fully abutted from the innerwall (41) to the front wall (35) with an oil film (70) therebetween. Oilfilm (70) is a standard mineral oil used for sealing moving parts in gasvalve units. The thickness and viscosity of the oil film (70) werechosen to allow an operator to easily rotate the rotating disc element(40). The stationary disc element (30) provides temporary blocking ofthe gas flow by partitioning the inner chamber (1) between the channelforming the rear part of the inner chamber (1) in the body (10) from itsrear wall (31) and surrounding the control rod (20) from the lower part(24) and the rotating disc element (40) in the opposite direction. Eachpocket (47) formed on the inner wall (41) of the rotating disc element(40) such that it faces the front wall (35) of the stationary discelement (30) has a hemispherical structure and has a diameter of 0.5 to3 mm. By means of this size and form, when the rotating disc element(40) rotates, oil film (70) is fed from the pockets (47) so as tomaintain a predetermined critical thickness of 2-10 microns in theradial direction.

REFERANCE NUMBERS 1 Inner chamber 40 Rotating disc element 10 Body 41Inner wall 12 Inlet part 42 Cavity 14 Gas outlet 421 Rear end 15 Inletchannel 422 Narrow part 16 Outlet channel 423 Wide part 17 Safety outlet424 Front end 18 Retainer boundary 425 Baffle wall 20 Control rod 426Front edge 22 Upper part 43 Outer wall 24 Lower part 44 Mounting hole 26Cover 45 Expansion chamber 28 Compression spring 46 Circumferential edge30 Stationary discelement 47 Pocket 31 Rear Wall 48 Adaptor socket 32Through hole 50 Gasket 33 Circumferential Wall 60 Safety assembly 331Handle part 70 Oil film 34 Central hole 35 Front wall 36 Auxiliarythrough hole 37 Channel 38 Block

1. A gas valve comprising a body having an inlet channel and an outletchannel in gas flow connection via an inner chamber surrounded by body ;a stationary disc element fixed in the inner chamber and having athrough hole thereon having access to the gas outlet channel ; arotating disc element with an inner wall overlapping a front wall of thestationary disc element in a rotatable manner and a cavity that reachthe outlet channel through the through hole when rotated characterizedin that the front wall and the inner wall of the stationary disc elementand the rotating disc element facing each other, respectively, are atleast partially made of ceramic material.
 2. The gas valve according toclaim 1, wherein the stationary disc element and the rotating discelement are made of solid ceramic material.
 3. The gas valve unitaccording to claim 1, wherein a rear wall is provided parallel to thefront wall and the stationary disc elementis coupled by a peripheralwall between the front wall and the rear wall through a retainer wallforming the inner wall of the inner chamber .
 4. The gas valve unitaccording to claim 3, wherein a flexible gasket is compressed towardsthe gas outlet channelon the planar rear wall such that it surrounds thethrough hole in a gas-tight way.
 5. The gas valve unit according claim1, wherein an oil film is provided between the front wall and the innerwall ,surrounding the through hole and the cavity in a gas-tight way andadjusted to a predetermined viscosity so as to allow rotation on oneanother.
 6. The gas valve unit according to claim 5, wherein a pluralityof pockets are provided on the inner wall and store the oil dropletinside so as to feed the oil film during the rotation of the rotatingdisc element .
 7. The gas valve unit according to claim 1, wherein acontrol rod extends vertically outward by being attached to an outerwall of the rotating disc element .
 8. The gas valve unit according toclaim 7, wherein a cover surrounds the control rodfrom its upper part atone end and is fixed to the body at the other end.
 9. The gas valve unitaccording to claim 8, wherein a compression spring is adjusted withinthe cover such that it abuts against the inside of the cover from oneend and presses the rotating disc element from the other end.
 10. Thegas valve unit according to claim 1, wherein the stationary disc elementand the rotating disc element are manufactured or coated from a materialselected from the group consisting of alumina, silicon carbide, siliconnitride and zirconia.
 11. A gas cooker or heating device to which thegas valve unit is adapted according claim 1.